For example, various detection apparatuses are proposed which take an image of a view ahead of a vehicle, such as an automobile, by a camera installed in the vehicle to detect an object, such as a pedestrian and another vehicle, based on the taken image (refer to Patent Literature 1, Non Patent Literature 1). Such detection apparatuses detect an object and measure (estimate) the distance from the vehicle (camera) to the object and movement (speed) of the object.
Obtaining the position of and speed of the object can determine whether or not the object is dangerous for the vehicle. Then, if the object may be dangerous for the vehicle, an alarm about the danger is issued to the driver, or the brake is automatically controlled, which can support the driving of the driver.
Non Patent Literature 1 discloses a method of estimating the three-dimensional position and speed of an object from images taken by two cameras. Specifically, according to the method of Non Patent Literature 1, a parallax is obtained for each pixel from the two images taken by the two cameras. In addition, a shift (optical flow) for each pixel is calculated from successive frame images taken by one of the cameras. Then, the actual position and speed of the object are estimated by a Kalman filter by using the parallaxes and the optical flows as inputs.